Thorgan Hazard will join his older brother Eden at Stamford Bridge next season after Chelsea confirmed his signing from Lens.
The 19-year-old had only played 11 times for the Ligue 2 club but the Blues clearly see some potential in Hazard, who had just a year remaining on his contract at Lens, although they revealed the midfielder could be immediately loaned to another club.
"He will now join our Under-21 squad, managed by Dermot Drummy, to continue his pre-season training and a loan move is being considered to continue his development," read a statement on the club's official website.
Hazard's sibling Eden, who won the Ligue 1 player of the year last season, joined the west London club last month from Lille for a reported £32million.
While that sum will be nowhere near what was paid for Thorgan, the Blues may have unearthed a future talent.
He moved to Lens as a 14-year-old in 2007 and graduated into the senior squad last season. The Blues' newest recruit has also represented Belgium up to Under-19 level.
Should he and Eden both play for Roberto Di Matteo's side they will join Ray and Graham Wilkins, Ron and Allan Harris, John and Peter Sillett and Chris and William Ferguson as brothers who have played together in Chelsea's first team.
Meanwhile, the Blues confirmed three of their young players have gone on loan, with attacking midfielder Ulises Davila joining Spanish second division team Sabadell and striker Milan Lakovic and goalkeeper Matej Delac moving to Guimaraes in the Portuguese top flight.